7.4 Warm-Up: Area Review

7.4 Warm-Up: Area Review

Review the area of 2D figures

Area of a Rectangle

•  $A=bh\ \ \ or\ \ \ \ A=lw$  

• Area of a rectangle equals the base times the height, or...

• Area of a rectangle equals the length times the width

Fill in the Blanks

What is the are of the rectangle?

(NUMBER ANSWER ONLY)

(NO UNITS!!!)

Area of a Triangle

•  $A=\frac{1}{2}bh$  

• Area of a triangle is half of the base of the triangle times the height of the triangle (base of the triangle times the height of the triangle, divided by 2)

• REMEMBER: the base is always a side, and the height is always a right angle to the base

Fill in the Blanks

What is the area of the triangle?

(NUMBER ANSWER ONLY)

(NO UNITS!!!)

Area of a Circle

•  $A=\pi r^2$  

• Area of a circle equals 3.14 times the radius, times the radius again

• REMEMBER: radius is halfway across the circle

Fill in the Blanks

What is the area of the circle?

(NUMBER ANSWER ONLY)

(NO UNITS!!!)

Multiple Choice

What is the area of the half circle with a diameter of 8 (radius of 4)?
(hint: calculate the area of the whole circle, then divide by 2 to find half of it)

•  $50.24\ cm^2$   
  

•  $12.56\ cm^2$  
  

Compound Area

• Area of a compound figure can be found by:

• 1) identify the shapes in the compound figure

• 2) calculate the area of each shape

• 3) add the areas together

Fill in the Blanks

What is the compound area of this compound figure?

(NUMBER ANSWER ONLY)

(NO UNITS!!!)